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  <title>获取已定义的常量</title>
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  <div id="layout-content"><div id="reflectionclass.getconstant" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">ReflectionClass::getConstant</h1>
  <p class="verinfo">(PHP 5, PHP 7, PHP 8)</p><p class="refpurpose"><span class="refname">ReflectionClass::getConstant</span> &mdash; <span class="dc-title">获取已定义的常量</span></p>

 </div>

 <div class="refsect1 description" id="refsect1-reflectionclass.getconstant-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="modifier">public</span> <span class="methodname"><strong>ReflectionClass::getConstant</strong></span>(<span class="methodparam"><span class="type">string</span> <code class="parameter">$name</code></span>): <span class="type"><a href="language.types.declarations.html#language.types.declarations.mixed" class="type mixed">mixed</a></span></div>

  <p class="para rdfs-comment">
   获取已定义的常量。
  </p>
 </div>


 <div class="refsect1 parameters" id="refsect1-reflectionclass.getconstant-parameters">
  <h3 class="title">参数</h3>
  <p class="para">
   <dl>
    
     <dt>
<code class="parameter">name</code></dt>

     <dd>

      <p class="para">
       要获取的类常量的名称。
      </p>
     </dd>

    
   </dl>

  </p>
 </div>


 <div class="refsect1 returnvalues" id="refsect1-reflectionclass.getconstant-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   常量名称为 <code class="parameter">name</code> 的值。
   如果在类中没有找到该常量，则返回 <strong><code>false</code></strong> 。
  </p>
 </div>


 <div class="refsect1 examples" id="refsect1-reflectionclass.getconstant-examples">
  <h3 class="title">范例</h3>
  <p class="para">
   <div class="example" id="example-5153">
    <p><strong>示例 #1 使用 <span class="methodname"><strong>ReflectionClass::getConstant()</strong></span></strong></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /><br /></span><span style="color: #007700">class&nbsp;</span><span style="color: #0000BB">Example&nbsp;</span><span style="color: #007700">{<br />&nbsp;&nbsp;&nbsp;&nbsp;const&nbsp;</span><span style="color: #0000BB">C1&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">false</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;const&nbsp;</span><span style="color: #0000BB">C2&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'I&nbsp;am&nbsp;a&nbsp;constant'</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #0000BB">$reflection&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">ReflectionClass</span><span style="color: #007700">(</span><span style="color: #DD0000">'Example'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$reflection</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">getConstant</span><span style="color: #007700">(</span><span style="color: #DD0000">'C1'</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$reflection</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">getConstant</span><span style="color: #007700">(</span><span style="color: #DD0000">'C2'</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$reflection</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">getConstant</span><span style="color: #007700">(</span><span style="color: #DD0000">'C3'</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>以上例程会输出：</p></div>
    <div class="example-contents screen">
<div class="cdata"><pre>
bool(false)
string(15) &quot;I am a constant&quot;
bool(false)
</pre></div>
    </div>
   </div>
  </p>
 </div>


 <div class="refsect1 seealso" id="refsect1-reflectionclass.getconstant-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><span class="methodname"><a href="reflectionclass.getconstants.html" class="methodname" rel="rdfs-seeAlso">ReflectionClass::getConstants()</a> - 获取常量</span></li>
   </ul>
  </p>
 </div>


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